This data set shows orchard locations in Clarke and Frederick Counties, Virginia and Berkeley and Jefferson Counties, West Virginia where arsenical pesticides were likely used. The orchard locations are based on air photos and topographic maps prepared using information from the time period of extensive use of arsenical pesticides between the 1920s and 1960s. An orchard's presence in this data set does not necessarily indicate the use of arsenical pesticides on the site or that elevated arsenic and metal concentrations are present. Arsenical pesticides may have been used on part, or none, of the land and, under current land use, the land may have been remediated and no longer contain elevated arsenic and metal concentrations in soil.
The data set was created to be used in an assessment of soil contamination related to past use of arsenical pesticides in orchards in the northern part of the Great Valley region, Virginia and West Virginia. Previous studies have documented that elevated concentrations of arsenic, lead, and sometimes copper occur in the soils of former apple orchards (Veneman et al., 1983; Jones and Hatch, 1937).
Arsenical pesticide use was most extensive and widespread in agricultural applications from the 1920s to the late 1950s, and largely ceased agricultural use by the early 1960s in the nation. During this time period, lead arsenate was the most extensively used arsenical pesticide (Peryea, 1998), particularly in apple orchards. Other metal-bearing pesticides, such as copper acetoarsenite (Paris Green), Bordeaux Blue (a mixture of copper sulfate and calcium hydroxide), and organic mercury fumigants were used to a lesser degree in orchards (Peryea, 1998; Shepard, 1939; Veneman et al., 1983).
During the time arsenical pesticides were extensively used, federal and state pesticide laws did not require farmers to keep accurate records of the quantity, location, and type of arsenical pesticides used on their property, thus the quantity and distribution of this past arsenical pesticide use is not known in the region. Based on estimates from other areas (D'Angelo et al., 1996), cumulate application over the period of arsenical pesticide use may have been as much as 22.4 g/m2 of arsenic and 100 g/m2 of lead in orchard areas. In minimally disturbed orchard soils, arsenic and lead are largely retained in the top few centimeters of the soil horizon; intra-soil redistribution of these metals occurs but appears to be limited (Veneman et al. 1983; Peryea, 1998). Surface concentrations of arsenic and lead in undisturbed orchard soils where arsenical pesticides were used commonly exceed 20 mg/kg As and 100 mg/kg Pb (Veneman et al., 1983; Jones and Hatch, 1937).
The digital data set of orchard locations was used to aid assessment of the likely occurrence and distribution of arsenical pesticide residues in surface soils. Most areas of orchard cultivation were sited in areas overlying carbonate bedrock in the Valley and Ridge province.
This data set needed to be created since there was no reliable and complete land cover data set identifying areas under orchard cultivation during the time period of extensive use of arsenical pesticides in the study area as of the time of the study. The spatial database of orchard areas was compiled using twenty-seven USGS 7.5 minute series topographical maps covering the study area of Clarke and Frederick Counties, Virginia, and Berkeley and Jefferson Counties, West Virginia. These maps were published between 1943 and 1972 at 1:24,000 scale, with the oldest topographic map available from the US Geological Survey map archive for each area being chosen, going back only as far as the 1920s when use of arsenical pesticides started. Orchard areas on the topographic maps were traced in order to aid in the digitization of the sites. The topographic maps were then scanned and geographically referenced using ERDAS Imagine version 8.7, a raster editing program, turning them into rectifi
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USGS Numbered Series
Digital Data Set of Orchards Where Arsenical Pesticides Were Likely Used in Clarke and Frederick Counties, Virginia, and Berkeley and Jefferson Counties, West Virginia